Biofilm production in a novel polyextremophilic Bacillus subtilis: A strategic maneuver for survival

Abstract

Extremophiles are well-known to flourish in hostile extreme habitats. For instance, extremes of temperatures, acidic or alkaline environments, high pressure, UV irradiation, salinity and even presence of heavy metal concentrations. While extremophiles can survive in an individual extreme, polyextremophiles can survive in combinations of such extreme environmental niches. Polyextremophily mainly exists in two dimensional matrices of extreme conditions such as temperature and pH, temperature and salinity etc. It provides the potential to delineate from the habitability envelope by putting constraints on biological processes, and dislocating them from their natural niche. Microbial biofilm, which is an assemblage of microbes in extracellular polymeric substances, secreted by the microbes themselves not only play a huge role in microbial colonization, nutrient sequestration and quorum sensing but also protects the microbes from the aforementioned array of environmental hostilities.This paper deals with, a novel polyextremophilic strain of Bacillus isolated from the waters of The Ganges, at Gangotri situated in Uttarakhand, at an altitude of 3,415 m from sea level, on the Greater Himalayan range. The strain Bacillus subtilis BRAM_G1 (Accession Number: MW006633), was found to be tolerant to a huge plethora of extreme conditions ranging from temperature (from −20 °C to 110 °C), ultraviolet radiation (79200 μW/cm2), pH (1–12), salinity (8%) to heavy metal concentrations (arsenic, silver, iron etc.). On further investigation, the strains were found to produce enormous amounts of biofilm and a control laboratory strain of Bacillus sp. which did not produce biofilm was also found to be sensitive to the array of extreme conditions the novel strains survived. Thus, providing a conclusive proof about the role played by microbial biofilm formation as one of the survival strategies for inhabiting such extreme niches.